1. Field of the Invention
The present invention relates to a method and apparatus for supplying heated water to a large building. In particular, the invention relates to a method and apparatus for recovering heat from the condenser of an air conditioner compressor and utilizing recovered heat to heat water used in controlling the temperature of a large building.
2. Description of the Related Art
It is well known in the art to use hot water to control the temperature of a large building. The water may be heated by direct fired boilers, which burn natural gas or other fuel. The water may also be heated by electrical heating coils, or by boilers which produce steam which flows to heat exchangers, commonly called steam converters, to heat hot water.
The hot water is circulated to heating coils located throughout the building and returned to the boiler or steam converter to be reheated and again circulated to the heating coils throughout the building. The heating coils are used for heating the air within the building. Such heating coils are commonly located in the ducts or vents, sometimes referred to in the art as air handlers, supplying air to the various rooms in the building to heat the air flowing to the rooms when desired. Heated water supplied to such heating coils from direct fired boilers or steam converters is referred to herein as "reheat water".
Reheat water is used to heat air in the building at various locations throughout the building. The heating coils receiving reheat water are commonly located adjacent to cooling coils receiving chilled liquids or gases from air conditioning units. Both the cooling coils and the heating coils are commonly located adjacent to each other in the duct or air handler supplying conditioned air to a room in a building. If it is desired to raise the temperature of a room being cooled by air blown over cooling coils, reheat water is directed to heating coils which are located in the airstream. Thus the heating coils receiving reheat water can raise the temperature of the conditioned air being introduced into a room as desired.
Operation of direct fired boilers and steam boilers employing steam converters to provide reheat water requires large amounts of energy. When operating large air conditioning units during the summer it is still necessary for the large building employing such units to operate boilers to provide reheat water to maintain individual control of the temperature of various areas in the building being air conditioned.
U.S. Pat. No. 4,277,952 discloses a method and apparatus for conserving energy in an air conditioning system in which the air conditioning units are turned off and the cooling tower is operated when ambient conditions permit to provide cold water to heat exchangers. Chilled water needed to cool the building is circulated through the heat exchanger and the heat exchange is effected between the chilled water and the cool water supplied by the cooling tower.